Near-eye displays (NEDs) include head-mounted displays (HMDs) that can project an image directly into eyes of an observer. In use, the distance between the display screen of such a near-eye display and eyeballs is less than 10 cm. Generally, human eyes cannot clearly see the image at such a close distance. However, the near-eye display uses a specially designed lens array to focus an image and project the image onto the human retina. After processing by the visual neural system, a virtual large-scale image is presented in front of the user. Therefore, near-eye displays can be applied to virtual or augmented reality.
In an existing near-eye display device, as shown in FIG. 3A and FIG. 3B, a user wearing a near-eye display according to the present invention may encounter image defects in a near-sighted or far-sighted state.
The so-called “near-sighted state or far-sighted state” herein (that is, “visual acuity state of human eye” hereinafter) may be caused by zooming of human eyes, for example, the near-sighted state caused by focusing at a near position and the far-sighted state caused by focusing at a distant position, or may be caused by aberrations or defects (near-sightedness, far-sightedness, etc.) of eyes of an observer.
FIG. 3A illustrates a case of the near-sighted state, where an image on a display screen 301 is presented to a human eye 303 through a microlens array 302, and an image 304 is formed on the retina. In this case, there are gaps between subimages displayed on display regions (see the view in direction A). FIG. 3B illustrates a case of the far-sighted state, where there are overlaps between subimages displayed on display regions (see the view in direction B).
Therefore, it is necessary to provide a near-eye display having a simple structure and capable of adaptively displaying an image according to the visual acuity state (the near-sighted state or the far-sighted state) of eyes of the user.